This invention relates to ball joints, and more particularly it is concerned with a ball joint of the type which is used with a mechanism for steering or suspension of a motor vehicle. This invention provides improvements in or relating to a ball joint of the permanent lubrication type in which a bearing member made in one piece from a plastic material is used and the spring member is eliminated.
The ball joint of this type which uses a bearing member made in one piece offers the advantages of having few component parts and being simple in construction. On the other hand, since such bearing member encloses the spherical head of ball stud, its opening must be smaller than the diameter of the spherical head. In order to eliminate the difficulty with which the spherical head of the ball stud is inserted into the bearing member through this small opening, the bearing member should be flexible. Also, a rubber-like elastomeric material is employed for making the bearing member because it is necessary to utilize the compression resilience of the material to compensate for wear. The bearing material of this type is low in mechanical strength because of its character. This makes it necessary to increase the size of the ball joint to enable the ball joint to withstand a high load applied thereto.